1. Technical Field
The present disclosure relates to a needle plate having a first needle plate fixed to a sewing machine bed and a second needle plate detachably attached to the first needle plate, and a sewing machine provided with the needle plate.
2. Description of the Related Art
Conventional sewing machine have been provided with a needle plate screwed to an upper surface of the sewing machine bed (a bed portion) and having a needle hole through which a needle is penetrable and a rectangular hole through which a feed dog feeding a workpiece cloth is retractable. The sewing machine has also been provided with the horizontal hook mechanism disposed in the bed. In this type of sewing machine, when a bobbin thread is entangled with the horizontal hook mechanism or the periphery of the horizontal hook mechanism is cleaned, the needle plate is unscrewed thereby to be detached from the bed so that the horizontal hook mechanism and the periphery thereof are exposed. However, the needle plate necessitates positional adjustment relative to the needle, feed dog and the like when reattached to the bed. When the adjustment is not carried out accurately, there is a possibility that the needle or feed dog may collide with the needle plate.
In view of the above-described problem, the related art has proposed needle plates for a sewing machine which comprise a first needle plate having a needle hole and a rectangular hole and a second needle plate located above the first needle plate and a horizontal hook mechanism and in which only the second needle plate is detached from the bed so that necessary working can be carried out in the bed. For example, there has been proposed a needle plate provided with an engaging mechanism which is located on a back side thereof and engages the second needle plate with the first needle plate and a disengagement button operable at a surface side of the needle plate. The engaging mechanism includes a protrusion provided at the first needle plate side and a hole of leaf spring in engagement with the protrusion. When the disengagement button is depressed downward, the protrusion is adapted to be disengaged from the hole. As a result, only the second needle plate can be detached and the interior of the bed can be cleaned, and the first needle plate necessitating the positional adjustment need not be detached.
However, the detachment of the second needle plate from the first needle plate necessitates a first operation thrusting the disengagement button downward against an elastic force of the leaf spring of the engagement mechanism and a second operation pulling the second needle plate frontward while the disengagement button is kept depressed. More specifically, directions of operation forces effective in the first and second operations are opposite to each other. Accordingly, the second needle plate is difficult to detach and a two-staged operation is troublesome.